Chapter 1: I don't like history, let's change it

Teddy Lupin is enjoying his 6th year at Hogwarts with his boyfriend Theo (OC). Travelling back in time using timeturner is dangerous, but they can prevent a war and with that save many lifes. How? By saving Regulus Black and helping him find all horcruxes. Of course things are a little bit more complicated than that. What will happen when Teddy see a couple of familiar faces?